Sources of carbon for hepatic glycogen synthesis in the conscious dog
- PMID: 1864968
- PMCID: PMC295390
- DOI: 10.1172/JCI115342
Sources of carbon for hepatic glycogen synthesis in the conscious dog
Abstract
To identify the source(s) of carbon for the indirect pathway of hepatic glycogen synthesis, we studied nine 42-h fasted conscious dogs given a continuous intraduodenal infusion of glucose, labeled with [1-13C]glucose and [3-3H]glucose, at 8 mg.kg-1.min-1 for 240 min. Glycogen formation by the direct pathway was measured by 13C-NMR. Net hepatic balances of glucose, gluconeogenic amino acids, lactate, and glycerol were determined using the arteriovenous difference technique. During the steady-state period (the final hour of the infusion), 81% of the glucose infused was absorbed as glucose. Net gut output of lactate and alanine accounted for 5% and 3% of the glucose infused, respectively. The cumulative net hepatic uptakes were: glucose, 15.5 +/- 3.8 g; gluconeogenic amino acids, 32.2 +/- 2.2 mmol (2.9 +/- 0.2 g of glucose equivalents); and glycerol, 6.1 +/- 0.9 mmol (0.6 +/- 0.1 g of glucose equivalents). The liver produced a net of 29.2 +/- 9.6 mmol of lactate (2.6 +/- 0.8 g of glucose equivalents). Net hepatic glycogen synthesis totaled 9.3 +/- 2.5 g (1.8 +/- 0.4 g/100 g liver), with the direct pathway being responsible for 57 +/- 10%. Thus, net hepatic glucose uptake was sufficient to account for all glycogen formed by both the direct and indirect pathways. Total net hepatic uptake of gluconeogenic precursors (gluconeogenic amino acids, glycerol, and lactate) was able to account for only 20% of net glycogen synthesis by the indirect pathway. In a net sense, our data are consistent with an intrahepatic origin for most of the three-carbon precursors used for indirect glycogen synthesis.
Similar articles
-
Effect of hepatic nerves on disposition of an intraduodenal glucose load.Am J Physiol. 1993 Sep;265(3 Pt 1):E487-96. doi: 10.1152/ajpendo.1993.265.3.E487. Am J Physiol. 1993. PMID: 8214056
-
Disposition of a mixed meal by the conscious dog.Am J Physiol. 1994 Apr;266(4 Pt 1):E666-75. doi: 10.1152/ajpendo.1994.266.4.E666. Am J Physiol. 1994. PMID: 8178989
-
Effects of hyperglycemia on hepatic gluconeogenic flux during glycogen phosphorylase inhibition in the conscious dog.Am J Physiol Endocrinol Metab. 2004 Apr;286(4):E510-22. doi: 10.1152/ajpendo.00211.2003. Epub 2003 Nov 25. Am J Physiol Endocrinol Metab. 2004. PMID: 14644767
-
Indirect versus direct routes of hepatic glycogen synthesis.FASEB J. 1989 Sep;3(11):2277-81. doi: 10.1096/fasebj.3.11.2673899. FASEB J. 1989. PMID: 2673899 Review.
-
Enhancement of hepatic glycogen by gluconeogenic precursors: substrate flux or metabolic control?Am J Physiol. 1990 Jun;258(6 Pt 1):E899-906. doi: 10.1152/ajpendo.1990.258.6.E899. Am J Physiol. 1990. PMID: 2193531 Review.
Cited by
-
_targeting hepatic glucose metabolism in the treatment of type 2 diabetes.Nat Rev Drug Discov. 2016 Nov;15(11):786-804. doi: 10.1038/nrd.2016.151. Epub 2016 Aug 12. Nat Rev Drug Discov. 2016. PMID: 27516169 Free PMC article. Review.
-
Morning Engagement of Hepatic Insulin Receptors Improves Afternoon Hepatic Glucose Disposal and Storage.bioRxiv [Preprint]. 2024 Sep 27:2024.09.25.614969. doi: 10.1101/2024.09.25.614969. bioRxiv. 2024. Update in: Diabetes. 2024 Nov 27:db240786. doi: 10.2337/db24-0786 PMID: 39386695 Free PMC article. Updated. Preprint.
-
The mitochondrial isoform of phosphoenolpyruvate carboxykinase (PEPCK-M) and glucose homeostasis: has it been overlooked?Biochim Biophys Acta. 2014 Apr;1840(4):1313-30. doi: 10.1016/j.bbagen.2013.10.033. Epub 2013 Oct 28. Biochim Biophys Acta. 2014. PMID: 24177027 Free PMC article. Review.
-
Exercise-Induced Improvements to Whole Body Glucose Metabolism in Type 2 Diabetes: The Essential Role of the Liver.Front Endocrinol (Lausanne). 2020 Aug 28;11:567. doi: 10.3389/fendo.2020.00567. eCollection 2020. Front Endocrinol (Lausanne). 2020. PMID: 32982968 Free PMC article. Review.
-
Importance of peripheral insulin levels for insulin-induced suppression of glucose production in depancreatized dogs.J Clin Invest. 1992 Nov;90(5):1769-77. doi: 10.1172/JCI116051. J Clin Invest. 1992. PMID: 1430203 Free PMC article.
References
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Miscellaneous